关于对流免疫电泳和琼脂双向扩散试验的研究

对流免疫电泳和琼脂双向扩散是免疫学技术常用的沉淀试验方法之一。目前已广泛地应用于病毒、细菌、寄生虫和毒素等抗原抗体的检测、鉴别和分类。本试验通过肠道革兰氏阴性菌的抗原分析,进而掌握此法的特点和规律。现将结果报道如下。     

溶菌酶的活性测定方法

溶菌酶是一种与单核 -巨噬细胞系统有关的非特异防御机制 ,参与机体的免疫作用 ,测定溶菌酶活性值日益受到临床重视。国内外目前采用比浊法 ,琼脂板扩散法 ,比色测定法 ,琼脂火箭糖电泳法和高效液相色谱法。前两种方法较为常用 ,但干扰因素多 ,实验结果的重现性差 ;比色法操作简单但误差较大。以琼脂火箭糖电泳法和高效液相色谱法的测定效果最为理想。     

蚊虫胃血血源鉴定方法简介

蚊胃血血源鉴定是蚊媒病流行病学调查的重要内容。鉴定方法以往多采用沉淀试验,近10年来在方法学上有许多发展和改进。一、琼脂双向扩散试验法:该法根据蚊胃血与抗血清在琼脂平板上相向扩散形成的白色沉淀线判定结果,敏感性较环状沉淀法差,但简单易行,对多重食性蚊虫胃血的鉴别有价值,并可提供永久记录。二、醋酸纤维膜微量免疫扩散法:原理与琼脂双向扩散试验相似,结果判断需经染色,其敏感性和特异性高于沉淀法。三、血红蛋白结晶法:该法以待鉴定蚊胃血的血红蛋白结晶与实验室制备的人及动物血红蛋白结晶进行形态比较而判别血源。对不溶性血…     

单核巨噬细胞在病毒感染中的作用及抗体介导的感染增强

<正> 人类和动物的病毒感染分为初次感染和再次感染。在初次感染的恢复期及再感染时,机体的特异性免疫系统起着重要的作用。然而在初次感染的早期,即特异性免疫系统尚未被激活之前,防止病毒的入侵、繁殖和扩散以及消灭病毒,机体早已存在的非特异免疫系统和各种屏障却起决定性作用。单核巨噬细胞位于许多病毒最初感染的部位以及它     

植物病毒及其卫星RNA在寄主体内的移动和系统分布

植物病毒与动物病毒有多方面的不同,主要包括:大多数植物病毒的感染需要微伤口(少数靠内吞作用;包膜病毒靠融合方式),而动物病毒的感染则需要受体.在植物病毒进入细胞或从一个细胞扩散到周围未被感染的细胞时都会遇到一些障碍,如细胞壁和细胞质膜.到目前为止,尚未在植物细胞中发现有病毒受体参与侵染的证据.     

旅游开发对景观边缘植物溢出效应的影响

人类活动导致的景观改变能形成大量的生境缀块和边缘结构,对植物扩散产生重要影响。以植物个体运动生态学——种子扩散模式作为分类依据,对兴凯湖自然保护区游憩带与非游憩带、交通廊道与非交通廊道中动物扩散物种、风扩散物种、无助力扩散物种(包括重力扩散、弹射扩散等短距离扩散的物种)以及全部物种的边缘溢出效应分别进行对比分析。结果显示,游憩带动物扩散物种和全部物种的边缘溢出效应均明显弱于非游憩带;而风扩散物种在游憩带和非游憩带均有大量溢出;无助力扩散物种在这两个实验区的溢出效应均不明显。交通廊道中动物扩散物种的溢出效应显著弱于非交通廊道,但风扩散物种却明显强于非交通廊道;无助力扩散物种在两种廊道类型中同样只有少量溢出,且距离相对较短;总体溢出效应并未发现显著差异。这些结果表明,旅游开发对植物运动生态学产生了影响,最终导致了溢出效应的改变。     

烟草果胶甲基酯酶（PME）基因的克隆及功能分析(英)

为了研究果胶甲基酯酶（pectin methyl-esterase,PME）（EC 3.1.1.11）与植物病毒运动蛋白之间的相互作用,应用RT-PCR方法从烟草(Nicotiana benthamiana)中克隆了PME基因,并测定了全序列(GenBank登录号AY238968).序列分析显示该基因由两个保守的结构域组成(PMEI和pectinesterase). DNA印迹结果表明,该基因在基因组中存在多个拷贝,蛋白质印迹表明,植物总蛋白中存在两种形式的PME蛋白,但RNA印迹结果显示,在烟草细胞中只检测到全长的PME转录产物.酵母双杂交结果表明,PME与水稻矮缩病毒Pns11(具有非特异的核酸结合活性)之间存在相互作用,而没有检测到PME与已知的运动蛋白Pns6之间的相互作用,推测Pns11蛋白可能参与了水稻矮缩病毒粒子的运动.     

酶联免疫吸附试验在传染病血清学方面的作用

<正>血凝抑制(HAI)、间接血凝(IHA),补体结合试验(CF),病毒中和试验(VN)或琼脂扩散试验已经成为应用于传染病中定量测定特异性抗原或抗体的常规方法。然而,这些方法都受到许多限制。操作程序复杂,需要较长时间,各种试剂和样品的预先处理或滴定,同时各个实验室之间缺乏统一的标准。     

运动蛋白介导的病毒在植物体中的传播

综述了病毒在植物寄主内扩散中的运动蛋白的作用。由病毒基因组编码的运动蛋白与病毒核酸形成运动蛋白核酸复合物,介导病毒扩散。在病毒复制与扩散过程中,运动蛋白与宿主细胞内质网、高尔基体、细胞骨架、胞间连丝发生作用,并受细胞果胶甲基脂酶、包含体、β-1,3-葡聚糖酶、磷酸化等因素的影响,形成了植物体内遗传物质系统性运输的一个模式。     

中国大陆水稻黄矮病与台湾省水稻暂黄病的血清学鉴定

以前的文献报道我国大陆水稻黄矮病和台湾省的水稻暂黄病的病状、传毒介体和病毒形状均相似或相同,被认为是同一病害,但没有做过血清学反应的鉴定比较。本试验采用琼脂扩散法和双抗体夹心法(PAS-ELISA),对上述两病原的抗血清与黄矮病株提取液和带毒黑尾叶蝉研磨液进行了琼脂双扩散和酶联免疫反应的比较研究。黄矮病毒提取液与暂黄病毒抗血清的琼脂双扩散产生清晰的沉淀带,在ELISA试验中均为典型的阳性反应;黄矮病毒抗血清和暂黄病毒抗血清对生物测定虫的同一头黑尾叶蝉研磨液的测定结果,阳性虫附合率98％,病原田捕捉虫的符合率为100％。根据以上结果可以认为两种抗血清同源,即中国大陆水稻黄矮病与台湾省水稻暂黄病为同一病害。     

Biosafety of plant viruses for human and animals

Currently, virions and virus-like particles (VLPs) of plant viruses are considered as the basis for the development of new biotechnologies for human and veterinary medicine, including production of modern and safe vaccines, targeted delivery systems, and novel diagnostic preparations, as well as for production of therapeutic proteins in plants. Despite the fact that plant viruses cannot replicate in vertebrates, there are data that they are able to reproduce one or another phase of the infectious cycle in mammalian cells. Moreover, it was shown that plant viruses can be permanently present in a human and animal organism and can use it as a vector. In the review, the results of biocompatibility, toxicity, teratogenicity, and distribution of plant viruses are presented. Based on recent data, it can be affirmed that plant viruses are safe for humans and animals. It was shown that the virions are biodegradable and are easily eliminated from an organism of laboratory animals. Furthermore the virions and VLPs of plant viruses are highly immunogenic and presentation of antigenic determinant of human and animal pathogens on their surface allow to simulate a safe viral particle that is able to replace live attenuated vaccines.     

A hypercycle theory of proliferation of viruses and resistance to the viruses of transgenic plant

A set of dynamical equations for the proliferation of two typical viruses TMV and PVY has been derived from the reaction equations describing their replication, assembly and translation. These equations can be seen as the generalization of hypercycle theory to the system. The quantitative explanation on the phenomena of proliferation of plant virus and the mechanism of resistance to the disease of transgenic plant is offered. The phenomenon of specific cessation of minus-strand RNA accumulation in the proliferation of TMV, the cross-protection of plant viruses and the mechanism of resistance to viruses of transgenic plant are discussed based on the computer simulation of the proliferation of viruses and the prediction of the secondary structure of the genomic RNA.     

Geminivirus genes and vectors

The geminiviruses are very small plant viruses with circular single-stranded DNA genomes. Recent advances have identified genes involved in replication, spread of virus or DNA in the plant, and insect transmission. Gene replacement experiments suggest that useful plant gene expression vectors can be constructed from these viruses.     

罗汉果雌雄株同工酶性别鉴定研究

采用电泳技术结合同工酶染色,分析了罗汉果雌雄株叶片的过氧化物酶同工酶、酯酶同工酶、超氧化物歧化酶同工酶、多酚氧化酶同工酶和过氧化氢酶同工酶。结果表明:罗汉果雌雄叶片在同工酶谱上,存在着与性别性状相关的酶带;雌雄间的差异酶带在每一种同工酶中均有一条以上,可作为罗汉果雌雄株间的性别鉴定。此外,还比较了高产、低产、不结果雌株之间同工酶的酶带和活性差别。     

A guide to the contained use of plant virus infectious clones

Plant virus infectious clones are important tools with wide‐ranging applications in different areas of biology and medicine. Their uses in plant pathology include the study of plant–virus interactions, and screening of germplasm as part of prebreeding programmes for virus resistance. They can also be modified to induce transient plant gene silencing (Virus Induced Gene Silencing – VIGS) and as expression vectors for plant or exogenous proteins, with applications in both plant pathology and more generally for the study of plant gene function. Plant viruses are also increasingly being investigated as expression vectors for in planta production of pharmaceutical products, known as molecular farming. However, plant virus infectious clones may pose a risk to the environment due to their ability to reconstitute fully functional, transmissible viruses. These risks arise from both their inherent pathogenicity and the effect of any introduced genetic modifications. Effective containment measures are therefore required. There has been no single comprehensive review of the biosafety considerations for the contained use of genetically modified plant viruses, despite their increasing importance across many biological fields. This review therefore explores the biosafety considerations for working with genetically modified plant viruses in contained environments, with focus on plant growth facilities. It includes regulatory frameworks, risk assessment, assignment of biosafety levels, facility features and working practices. The review is based on international guidance together with information provided by plant virus researchers.     

Gene amplification and expression by RNA viruses and potential for further application to plant gene transfer

The great majority of plant viruses encapsidate messenger-sense ssRNA and have no natural DNA phase in their life cycle. Despite their RNA nature, essentially any desired change can be introduced into such genomes by using recombinant DNA techniques with suitably constructed, expressible viral cDNA clones. For some viruses such as brome mosaic virus, these methods have been used to define the sequences controlling RNA-directed genomic RNA replication and the expression of internal genes via subgenomic mRNAs. The results suggest a surprising degree of genetic flexibility, which appears to be reflected in the varied gene complements and genetic organizations of presumably related plant and animal RNA viruses sharing conserved replication genes. Foreign genes inserted in such RNA virus genomes can be amplified and expressed to a high level in transfected plant cells. In addition to the potential use of such viruses as episomal expression vectors, it should be possible to couple the viral pathways of RNA-dependent RNA synthesis to amplify and to further regulate the expression of genes transformed into plant chromosomes.     

Exploring the diversity of plant DNA viruses and their satellites using vector-enabled metagenomics on whiteflies

Current knowledge of plant virus diversity is biased towards agents of visible and economically important diseases. Less is known about viruses that have not caused major diseases in crops, or viruses from native vegetation, which are a reservoir of biodiversity that can contribute to viral emergence. Discovery of these plant viruses is hindered by the traditional approach of sampling individual symptomatic plants. Since many damaging plant viruses are transmitted by insect vectors, we have developed "vector-enabled metagenomics" (VEM) to investigate the diversity of plant viruses. VEM involves sampling of insect vectors (in this case, whiteflies) from plants, followed by purification of viral particles and metagenomic sequencing. The VEM approach exploits the natural ability of highly mobile adult whiteflies to integrate viruses from many plants over time and space, and leverages the capability of metagenomics for discovering novel viruses. This study utilized VEM to describe the DNA viral community from whiteflies (Bemisia tabaci) collected from two important agricultural regions in Florida, USA. VEM successfully characterized the active and abundant viruses that produce disease symptoms in crops, as well as the less abundant viruses infecting adjacent native vegetation. PCR assays designed from the metagenomic sequences enabled the complete sequencing of four novel begomovirus genome components, as well as the first discovery of plant virus satellites in North America. One of the novel begomoviruses was subsequently identified in symptomatic Chenopodium ambrosiodes from the same field site, validating VEM as an effective method for proactive monitoring of plant viruses without a priori knowledge of the pathogens. This study demonstrates the power of VEM for describing the circulating viral community in a given region, which will enhance our understanding of plant viral diversity, and facilitate emerging plant virus surveillance and management of viral diseases.     

口岸植物检疫脱毒处理技术研究进展

植物病毒影响植物的生长和发育,尤其是植物病毒的传染性及增殖性对一种或者一类植物的危害巨大。为了防范植物病毒随寄主贸易跨境传播危害,本文阐述了茎尖培养脱毒、热处理脱毒、热处理结合茎尖脱毒、离体微型嫁接、化学处理结合茎尖脱毒和低温疗法等脱毒技术,对应用于口岸检疫性病毒的不同脱毒方法进行了综述和分析,同时对今后植物检疫脱毒研究方向进行了展望。     

The pollen virome: A review of pollen-associated viruses and consequences for plants and their interactions with pollinators

The movement of pollen grains from anthers to stigmas, often by insect pollinator vectors, is essential for plant reproduction. However, pollen is also a unique vehicle for viral spread. Pollen-associated plant viruses reside on the outside or inside of pollen grains, infect susceptible individuals through vertical or horizontal infection pathways, and can decrease plant fitness. These viruses are transferred with pollen between plants by pollinator vectors as they forage for floral resources; thus, pollen-associated viral spread is mediated by floral and pollen grain phenotypes and pollinator traits, much like pollination. Most of what is currently known about pollen-associated viruses was discovered through infection and transmission experiments in controlled settings, usually involving one virus and one plant species of agricultural or horticultural interest. In this review, we first provide an updated, comprehensive list of the recognized pollen-associated viruses. Then, we summarize virus, plant, pollinator vector, and landscape traits that can affect pollen-associated virus transmission, infection, and distribution. Next, we highlight the consequences of plant–pollinator–virus interactions that emerge in complex communities of co-flowering plants and pollinator vectors, such as pollen-associated virus spread between plant species and viral jumps from plant to pollinator hosts. We conclude by emphasizing the need for collaborative research that bridges pollen biology, virology, and pollination biology.     

Climate change effects on physiology and population processes of hosts and vectors that influence the spread of hemipteran-borne plant viruses

Plant virus diseases constitute one of the limiting factors to the productivity of agriculture. Changes in host plants and insect vector populations that might result from climate change (their geographical distribution range, their densities, migration potential and phenology) could affect the spread of plant viruses. At the individual level, alterations in plant physiological processes that are relevant to their molecular interactions with viruses, like changes in metabolism, leaf temperature, and their effects on some processes, like the temperature-sensitive antiviral resistance based in RNA silencing, can also influence the ability of individual plants to control viral infections. In order to assess the impact that climate change may have on the incidence and spread of hemipteran-borne plant viruses, its potential effects on virus/plant interactions and hemipteran insect vectors, as well as other operating processes, which could exacerbate or mitigate them, are identified and analyzed in this review.